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Vitamins
Vitamin K
An essential fat-soluble vitamin critical for blood clotting, bone health, and cardiovascular function
Quick Facts
Daily Needs
90-120 mcg for adults, with variations based on age and sex
Importance
Vitamin K is essential for blood coagulation, bone mineralization, cardiovascular health, and regulation of cellular functions.
Key Functions
- •Blood clotting (coagulation)
- •Bone mineralization and development
- •Prevention of arterial calcification
- •Regulation of cell growth
- •Anti-inflammatory function
- •Blood sugar regulation
- •Support of cardiovascular health
- •Maintenance of brain function
- •Protein activation through carboxylation
- •Energy metabolism
Deficiency Signs
- •Easy bruising
- •Excessive bleeding from wounds or injuries
- •Nosebleeds
- •Bleeding gums
- •Heavy menstrual periods
- •Blood in urine or stool
- •Poor bone health and increased fracture risk
- •Calcification of blood vessels and soft tissues
- •Impaired wound healing
Excess Signs
- •Rare from dietary sources
- •Synthetic form (K3) can cause toxicity
- •Can interfere with blood-thinning medications
- •Jaundice (in infants with large synthetic doses)
- •Hemolytic anemia (with high doses of synthetic forms)
Best Food Sources
- •Leafy green vegetables (kale, spinach, collards)
- •Cruciferous vegetables (broccoli, Brussels sprouts)
- •Vegetable oils (soybean, canola)
- •Fermented foods (natto, sauerkraut)
- •Liver
- •Eggs
- •Cheese (especially hard cheeses)
- •Pork
- •Chicken
- •Green tea
Absorption Facts
- •Fat-soluble - requires dietary fat for absorption
- •Absorption occurs in the small intestine
- •Vitamin K1 (phylloquinone) from plant foods is less bioavailable than K2 (menaquinones)
- •Gut bacteria produce vitamin K2 that can be absorbed
- •Certain antibiotics can reduce vitamin K production by gut bacteria
- •Bile is necessary for proper absorption
- •Absorption efficiency for dietary K1 is generally low (5-15%)
- •K2 forms have better absorption and longer half-life than K1
Special Considerations
- •People taking blood-thinning medications (like warfarin) should maintain consistent vitamin K intake
- •Newborns often receive vitamin K injections to prevent bleeding
- •Certain conditions (cystic fibrosis, celiac disease) may reduce absorption
- •Antibiotics can reduce vitamin K production by gut bacteria
- •Vitamin K works synergistically with vitamins D and A for bone health
- •Different forms (K1 vs K2) have somewhat different functions and benefits
- •Vitamin K2 seems particularly important for cardiovascular health
- •MK-7 form of K2 has the longest half-life and best bioavailability
About Vitamin K
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